The specific aim of this application is to acquire a state-of-the-art high performance MALDI-TOF mass spectrometer at the University of Pennsylvania to meet the needs of researchers concerned with studies of proteins, peptides, and other biomolecules. Specifically, the proposal intent is to expand the capabilities of the existing Protein Chemistry Laboratory (PCL) in the School of Medicine. The core facility is a state of art microchemical core facility offspring, to the entire University, the following services: 1) peptide synthesis, purification, and immunogenic coupling 2) peptide modifications 3) protein purification 4) tryptic peptide preparations 5) protein microsequencing 6.) mass spectroscopy and 7) training in protein purification and analysis. This instrument will enable us to a) obtain highly accurate molecular weight data on low pmole to femtomole amounts of peptides and proteins and permit rapid mass mapping identification of proteins whose cDNA-derived sequence information exists in the ever expanding databases. This approach is becoming essential to the management of protein sequencing resources available in an all-encompassing protein core laboratory like the PCL. Post source decay (PSD) and Collisionally induced dissociation (CID) features coupled with accurate mass data will provide partial sequence information on peptides even if present in a mixtures of N- terminally blocked. Structural problems on proteins and other biomolecules difficult or not approachable with conventional techniques will be addressable. Significantly the instrument will be integrated into all aspects of protein chemistries performed at the PCL such as Edman sequencing and peptide synthesis projects. In summary the new instrumentation will provide high-level-of-confidence answers for problems involving, natural product and expression product analysis, protein design, peptide synthesis, amino acid sequencing, ligand identification, post-translational modification identification., and protein identification through accurate mass mapping, characterization of non-protein biomolecules. We have identified a core of 10 major user research projects, from departments spanning four Penn schools (Art & Sciences, Dental Medicine, Veterinary Medicine and Medicine). The areas of interest include, protein-protein interactions, phylogeny of immune system, gene expression and protein design, anesthesia-related chemical modification of proteins, disulfide linkage determination, and biology of cell-growth and differentiation. Several people have already benefitted from interaction with our core and the new instrumentation will enhance the quality and quantify of results connected with future investigations of the various participating laboratories.